Circuit breaker



Feb. 27, 1945. T. M. COLE CIRCUIT BREAKER Filed Jan. 50, 1942 3 Sheets-Sheet l 5 200 34 I80 24,24 42 we 4 L98 22, 4 64 INVENTOR- THom/is, M (OI-E BY I A TTORNEY.

Feb. 27, 1945.

Filed Jan. 30, 1942 3 Sheets-Sheet 2 m H m M O o W Z M] WI 0 I m I: m 12 w w N E m 4 I I I U m x I 6 |\l 0 I U 35 Y B 8 6 0 I 6 l I \l 6 o I E w l 1 5 H l NJ I\\ ATTORNEY.

Patented Feb. 27 1945 Thomas M. Cole, New York, N. Y., assignor to Federal Electric Products Company, Inc., Newark, N. J., a corporation of New Jersey Application January 30, 1942, Serial No. 428,880

8 Claims.

This inventionrelates to circuit breakers and, more particularly, to circuit breakers of the type disclosed in United States Letters Patent No. 2,242,717, granted upon an application filed by me and Christopher I. Smith. This application is a continuation in part of my application Serial No. 412,356, filed September 25, 1941, Patent No. 2,362,051.

One object of the present invention is the provision in a circuit breaker of the above indicated type of means for facilitating the adjustment of the thermostatic device which controls the tripping of the breaker to open condition pursuant to the occurrence of an overload.

Another object of the invention is the provision of an improved assembly unit comprising the operating member and the companion contact members which ar carried by or secured thereto,

whereby to facilitate the assembly of these parts as a unit in the casing of the circuit breaker and with the other parts thereof.

Another object of the invention is the provision of a casing of improved construction and having arc chutes formed as integral parts of said casing.

The above and other objects, features and advantages of the invention will be more particularly described in the following specification and pointed out in the claims, and for a more complete understanding thereof reference is to be had to the accompanying drawings in which, for the purpose of illustration, the presently preferred embodiment of the invention is shown.

In the drawings:

Fig. 1 is a perspective view of a circuit breaker embodying the present invention;

Fig. 2 is a side view of the circuit breaker, with the casing cover removed, showing the breaker in manually opened condition;

Fig. 3 is a bottom view of the circuit breaker;

Fig. 4 is a View similar to Fig. 2' showing the circuit breaker closed;

Fig. 5 is a view similar to Fig. 2 showing the tripped condition of the circuit breaker;

Fig. 6 is an end view of the circuit breaker;

Fig. '7 is a sectional View of part of the circuit breaker on the line 1-1 of Fig. 8;

Fig. 8 is a cross sectional view On the line 88 of Fig. l; v

Fig. 9 is a side View of the casing itself, the cover being removed;

Fig. 10 is a View partly in section and partly in elevation on the line l0l0 of Fig. 4.

Referring now to the drawings in detail, the circuit breaker embodying the present invention I engages the edges 28 and 30 of end walls I6 and provided with a removable cover l2 preferably which project laterally of the casing beyond the.

edges 28 and 30 of end walls 16 and i8, respectively, the free ends 32 of said parts 24 and 2E projecting to the plane of the outer edge portions 34 of bottom wall 22.

vided with thickened portions36, 38, 48, 42 and contact membe 16 is fixed to a metal arm '18,,

comprises a casing Ill preferably molded in one parts '24, 26 and 34.

projecting end portion 48 which fits in a recess 44 provided with holes extending therethrough for bolts or the like 46 by which said cover I2 is removably secured in position. When cover i2 is fastened in position the inner surface thereof l8, the edges of top wall 20 below parts 2 and 2B, and the thickened portions 40', 42 and A l adjacent bottom wall 22, and the outer surface of cover 12 is preferably flush with the edges'of Said cover'ha's a'lower 50 in the bottom wall 22 and which projects beyond said bottom wall to the plane of integral parts 52 and 54 on bottom wall 22. Cover l2'has an upperintermediate portion 56 which projects within the recess formed between the confronting edges of parts 24 and 26, and rear wall M of' the casing has an upper intermediate portion 58 which confronts said part 56 of cover I 2. Parts 56, 58 and the confronting edges of parts 24 and 26 define an opening 60 in the top wall ofthe casing for the knob 62 of the switch operating member 64 which will presently be more specifically described.

Said switch operating member 64 is molded or otherwise made of insulation material, for ex ample, Bakelite, and is pivotally mounted in the casing preferabl in the manner hereinafter to be detailed. Said switch operating member 64 comprises a body portion '66 having an arcuate segmental portion 68 which extends preferably.

for th full width of the casing and closes opening 60 through which knob 62 projects, in all positions of said knob. A contact member W is mountedin fixed relation to operating member 64, being carried by a metal plate or bracket 12 secured to body portion 66 of operating member 64 by a screw 14. Anedge of plate '32 abuts a raised portion 15 on member 64. The companion carried by operating member. and pivotally mounted thereon. More particularly, arm 18 is pivotally mounted at its intermediate part 8t on. the circular shank portion 82 of a pin 84in position between a boss 86 formed on body portion 66 of operating member 64 and the head 83 of said pin. A part 90 of the stem of pin 84 is knurled and fits with a forced fit into the. axial opening 92 of body portion 66, as show'n'inFig. 8,

Said.

Said casing is pro thus fixedly securing said pin to said operating member in said opening. Part 82 of the pin is larger than the rest of the shank of the pin and forms a shoulder 93' which engages boss 86 to limit the movement of the pin into said opening 92 when the pin is entered into said opening. Th end portion 93a of said pin is preferably smooth and somewhat smaller in diameter than opening 92 to facilitate mounting of the pin. When shoulder 93 is adjacent boss 86, the space between said boss and the confronting surface of the head of the pin is but slightly wider than the thickness of the adjacent part of arm 86, so that movement of said arm axially of member 64 is prevented and contact members I6 and I6 are held in properly aligned positions.

A circular hub portion or trunnion 94 is formed on operating member '64 and is journalled in cylindrical recess 96 formed in the inner surface of casing Wall I4. The head 88 of pin 84 is circular and is journalled in a cylindrical recess 98 provided in a boss 99 provided on the inner surface of easing cover I2, recesses 96 and 98 being in 'axial alignment. Thus, switch operating member 64 is pivotally mounted in the casing and arm I8 is pivotally mounted on said switch operating member, being journalled for turning movement on pin 84. Arm I8 is biased for movement in a clockwise direction (viewing Fig. 2) by a spring I66 which has an intermediate portion I62 thereof coiled around boss 86 and which has end portions I64 and I66 in engagement with arm I8 and one end of the arcuate segmental portion 68, respectively. A fibre strip I68 is secured to the body portion 66 of switch operating member 64 between the latter and bracket I2 and arm I8 and as shown in Fig. 10 is folded over the adjacent edge N6 of body portion 66 to protect the adjacent part of the latter against deterioration by heat of the arcs which might be drawn when the contact members are being separated.

As illustrated in Fig. 4, when the circuit breaker is closed arm I8 is held against movement in a clockwise direction by the thermostat c or bimetallic strip H2 which is electrically connected to arm 18 by a flexible connecting member or pigtail H4. When an overload occurs said strip H2 is flexed laterally to the right (viewing Fig. 4) out of engagement with the adjacent end of arm I8, thus permitting spring I66 to move arm 18 in a clockwise direction for separating contact member I6 from the companion contact member I6, during which action switch operating member 64 moves from the position illustrated in Fig. 4 to the position illustrated in Fig. under the action of a spring I I6 which is clearly illustrated in Figs. 2. 4, 5 and 10. and which Spring H6 is V-shaped, as shown, and comprises parts H8 connected at their outer ends to an integral transverse end part I26 and at their other ends .to the inner convolution I2! of laterally spaced coils I22, the outer convolutions of said coil being in integral relation with the arms I24 which terminate in inturned or transverse portions I26. End portion I26 engages body portion '66 of the switch operating member 64 in a notched part I28 of the latter and end portions I26 engage the bottom wall 22 of the casing in a notched part I36 of the thickened portion 44 of said casing. It will be noted that spring H6 is organized with switch operating member 64 and with casing I6 in such manner that the circuit breaker when manually operated is opened and closed with a snap action and it is, of course, apparent that said spring H6 holds the contact members in either their engaged or disengaged positions in the non-tripped condition of the circuit breaker. Further, as explained above, when the circuit breaker is tripped spring I I6 moves switch operating member 64 from the position illustrated in Fig. 4 to the position illustrated in Fig. 5, so that the tripped condition is readily indicated by the position of knob 62 adjacent part 26 of the casing, and also so that the contact member I6 follows contact member I6 during part of the movement of the latter to its tripped condition.

An important feature of the present invention resides in the mounting of the bi-metallic strip H2 and in the provision of means for calibrating the circuit breaker for tripping thereof under 'will be presently described. It will be observed that during the movement of arm 18 to switch opening pos tion during which contact member 16 moves away from contact member I6, said last mentioned contact member I6 has a movement in a clockwise direction with switch operatin member 64 as described in the above mentioned patent whereby to delay somewhat the interruption of the circuit, this being desirable in certain cases, for example, when the circuit breaker is used in alternating current circuits.

It will be noted, however, that movement of contact member I6 concurrently with contact member I6 is of shortduration as the movement of contact member I6 is more rapid than the movement of contact member 16 although in the same direction.

' wall I8 thereof.

a predetermined load. For thesepurposes bimetallic strip H2 has an end portion I32 thereof positioned in a metal collar I34 which engages one leg I36 of an L-shaped terminal member I38. As shown more clearly in Fig. 7 collar I34 has an end wall I46 which is inclined approximately in the same direction. as the part I32 of said bi-metallic strip H2, and a calibrating screw I42 is threaded through an opening I44 in said wall and engages said part I32 of the strip. Preferably, as here shown, screw I42 i at right angles to part I32 of strip H2. Thus, by

adjusting said screw I42 the end portion I46 of bi-metallic strip H2 can be adjusted in relation to the free end of arm 78 so that by the flexing of the strip in response to the action of heat it disengages said arm under a predetermined load condition. It will be noted also that screw I42 holds the strip H2 in electrical engagement with leg I36 of terminal member I36 and also hold collar I34 in engagement with said terminal member.

The leg I 48 of terminal member I38 is releasably secured in position on the ledge I56 formed as an integral part of casing I6 adjacent th end Said leg I48 is releasably held in said position by a screw I52 which is passed through an opening I'54 in ledge I56 and which is threaded into leg I48 of terminal member I38. An opening I56 is provided in the lateral extension of bottom wall 22 of the casing to permit insertion of screw I52, and as shown in Fig. 2 after said screw is engaged with terminal mem ber I38 for holding the latter in position a fibre strip I58 is inserted in opening I56 for closin the latter.

A terminal connector I66 is secured to the upper surface of leg I48 of terminal member I38 on ledge I56 by said screw I52. Said terminal connector is provided with a screw I62 for securing the connecting wire (not shown) of the circuit in said terminal connector in electr'ical engagement therewith thereby to electrically connect said wire to terminal I38. The terminal at the other side of the circuit breaker is constituted by a flat metal strip I64 which is connected at its inner end to bracket 12 by a flexible connector or pigtail I66. Said terminal strip I64 lies flatwise in recesses I58, I10 and I12 formed in the upper edges of wall portions I14, I16 and in end wall i6, respectively. Movement of strip I64 transversely of said wall portions is prevented by the engagement of the inner end of said strip with an edge I18 of thickened portion 44 of casing wall 22 and by the engagement of a struck out portion I80 of said strip with the wall portion I14. Said strip I64 is held in position by easing cover I2, the inner surface of said cover engaging the adjacent surface of said strip While the opposite surface of the latter is engaged with the bottoms of said recesses I68, I10 and I12.

A terminal connector I82 is connected to the outer end of terminal strip I64 by a screw I84 which engages and passes through the laterally bent portion I86 of said strip and which holds the latter clamped against the strip I88 which is fixed in the terminal connector I82. A screw I90 on terminal connector I82 serves to hold a wire (not shown) at the other side of the circuit in releasable engagement with said terminal connector.

Casing In is provided with are chutes which also form passages for the exhaust of gases from the interior of the casing. Said arc chutes are formed by parts molded integrally with the casing. Thus, one are chute is constituted by a part I92 of wall I16 and the adjacent edge of part 36 cf the casing and is continuous with the passage I94 which terminates in an outlet opening I96 in end wall l6 of the casing. The other are chute is formed between wall I14 and the confronting part of wall I16 and communicates with a passage I98 which terminates in an outlet opening 200 in the bottom wall of the casing. As illustrated in Fig. the inlet end of the upper arc chute formed between parts 36 and I92 of the casing is adjacent to and in alignment with the space between separated contact members and 16 in the tripped condition of the switch. On the other hand, as illustrated in Fig. 2 when the switch is'manually opened the inlet end of the arc chute formed beween walls I14 and I16 is adjacent the space between the separated contacts 10 and 16. In other words, the inlet end of one are chute is adjacent the space between said contact members when they are separated under one condition of operation of the switch, and the inlet end of the other are chute is adjacent the space between said contact members when they are separated under a different condition of operation of the switch.

The manner of assembling the several parts of the circuit breaker with the casing will be apparent from the above description of the construction and relation of the casing and the various parts of the circuit breaker. It will be noted that the operating member 64 and all of the parts carried thereby can be assembled as a unit andinserted as a unit in the casing through the open side thereof before the cover I2 is attached. Likewise, it will be understood that the assembled unit can include the thermostatic strip I I2 and the terminal members I48 and I64. After the parts are inserted in the casing cover I2 is applied and fastened in position, thus completing the assembly. The circuit breaker can be mounted on any thereto in any suitable way, and as here shown casing I0 is provided with the above mentioned part 52 and with part 202 which has a slot 204 (Figs. 2, B and 9) for. a fastening screw (not shown). More particularly; for securing this circuit breaker to the panel, the outer end of part an opening in the panel, the head of said screw engaging the end 205 of part 202.

By reference to Fig. 3 it will be noted that slot 204 is open at the side I4 of' casing I0 by reason of the fact that said casing is molded. It will be understood that when casing I0 is fastened to the panel the latter is engaged at three points by the surfaces of parts 48, 52 and 54 in abutting relation with the confronting surface portions of the panel whereby the bottom wall 22' of the casing is spaced from the confronting panel surface. .Thus, a plurality of circuit breakers can be mounted on the panel in adjacent side by side relation without obstruction of opening 200 of passage I98.

While I have shown and described the pre.

ferred embodiment of my invention it will be understood that the latter may be embodied otherwise than as herein shown or illustrated,

and further it will be understood that in the illustrated embodiment certain changes in the details of construction and in the arrangement of parts may be made without departing from the spirit of the invention. Therefore, I do not wish to be limited to the construction herein illustrated or described except to the extent which may be required by the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In an electric circuit breaker, relatively movable contact members engageable with and disengageable from each other, an arm mounted for pivotal movement and carrying one of said contact members, a thermostatic strip releasably engaging said arm for preventing movement thereof in one direction, amounting member in which said strip is releasably and movably positioned, said mounting member having a wall portion substantially parallel to the adjacent face of said strip, and an adjustable member carried by said wall portion of the mounting member and releasably engageable with said adjacent face of said strip at right angles thereto for adjusting said strip in relation to said contact-carrying arm said strip being releasable from said mounting member by releasing said adjustable m'ember from engagement with said strip.

2. In an electric circuit breaker, relatively movable contact members engageable with and disengageable from each other, current responsive means includin a thermostatic strip for controlling the disengagement of said contact members, a collar in which a part of said strip is movably positioned, said collar having opposed wall portions, a terminal member having a part disposed between and engaging one of said-wall portions and one face of said part of the strip, and means adjustably mounted in the other of said wall portions of said collar and engaging the other face of said strip for releasably securing said strip and said collar to said part of the terminal member.

3. In an electric circuit breaker, relatively movable contact members engageable with and disengageable from each other, an electrical conductor arm mounted for pivotal movement and carrying suitable panel or support'and easily fastened one of said contact members, a thermostatic strip having one end thereof releasably engageable with said arm near one end thereof in electrical contact therewith and flexible out of engagement with said arm, an electrical terminal member, said strip having a part in engagement with a partof said terminal member in electrical contact therewith and a part movable toward and away from said part of the terminal member, said strip being mounted so that said end of the strip is movable toward and away from said end of said arm when said movable strip part is moved toward and away from said part of the terminal member, and means mounted for movement and releasably engaging said strip part for holding said strip part in engagement with said part of the terminal member and for adjusting said end of the strip in relation to said end of the arm, said strip being releasable from said terminal member by releasing said adjusting means from engagement with said strip.

4. In an electric circuit breaker, relatively movable contact members engageable with and disengageable from each other, an arm mounted for pivotal movement and carrying one of said contact members, a thermostatic strip having one end thereof releasably engageable with said arm near one end thereof and flexible out of engagement with said arm, a terminal member, said strip having a part in engagement with a part of said terminal member and a part movable toward and away from said part of the terminal member, said strip being mounted so that said end of the strip is movable toward and away from said end of said arm when said movable strip part is moved toward and away from said part of the terminal member, a collarembracing said part of the terminal member, said terminal-member part being positioned between one face of said strip part and an adjacent part of said collar, and a screw adiustably mounted in said collar at a part thereof opposite said first mentioned collar part and engaging the other face of said strip for releasably securing said strip and said collar to said part of the terminal member.

5. In an electric circuit breaker having relatively movable contact members engageable with and disengageable from each other within said casing, an operating member for engaging and disengaging said contact members, said operating member having an axial opening therein, a pin secured to said operating member in said opening and having a part projecting outwardly beyond one side of said operating member, said first mentioned part being knurled and frictionally engaging said operating member in said opening and thereby fixedly secured to said operating member, an arm pivotally mounted on said outwardly projecting part of said pin, one of said contact members being carried by said arm, and an enlarged part on said pin for holding said arm adjacent said side of the operating member.

6. In an electric circuit breaker, the sub-combination comprising an operating member formed of insulation material and adapted to be mounted for pivotal movement, a contact member carried by said operating member in fixed relation thereto, said operating member having an axial opening, a pin passing into said opening axially of said operating member and having a part projecting from said operating member and a cylindrical head at the end of said last mentioned part, an arm pivotally mounted on said projecting part of the pin at one side of said operating member,and held against axial movement by said head of said pin and the adjacent side of said operating member, the other side of said operating member having an integral cylindrical part projecting therefrom in axial alignment with said pin, the part of said pin in said opening being frictionally fixed to said operating member in said opening for preventing axial movement of said pin, and a contact member carried by said arm and movable by the latter into and out of engagement with said first mentioned contact member, said integral cylindrical part of said operating member and said head of said pin providing trunnions for pivotally mounting said operating member.

'7. In an electric circuit breaker, a casing, relatively movable contact members engageable with and disengageable from each other within said casing, an operating member for engaging and disengaging said contact members, said casing having a plurality of spaced openings therein, and means integral with said casing internally thereof forming a plurality of passages providing arc chutes leading from the interior of the casing to said openings, respectively, both of said contact members being movable to difierent spaced positions in said casing in different circuit interrupting positions under different conditions, respectively, one of said arc chutes having its inlet end adjacent the space between said contact members only when they are separated under one of said conditions and another of said are chutes having its inlet end adjacent the space between said contact members only when they are separated under a different condition.

8. In an electric circuit breaker, a casing having walls defining,a chamber, one of said walls at one side of said casing having a bearing recess formed therein, a cover removably secured to said casing and forming a wall of the casing at the opposite side thereof, said cover having a bearing recess in alignment with said first mentioned recess when the cover is secured in said wall-forming position thereof, an operating memoer positioned between said opposed walls and having parts journalled in said bearing recesses, respectively, companion relatively movable contact members in said casing operable by said operating member for engagement with and disengagement from each other, said casing having interior laterally spaced walls extending between said cover and the wall opposite thereto and defining an arc chute, said laterally spaced walls having free edges which are disposed adjacent said cover when the latter is in said wall-forming position thereof, each of said free edges of said laterally spaced walls having a recess therein, and a terminal member positioned in said recesses and electrically connected to one of said contact members and held in position in said recesses by said cover when the latter is secured to the casing, said terminal member extending across the space between said laterally spaced walls and having a part projecting through said casing to a point at the outerside thereof.

THOMAS M. COLE. 

